Quantum invariants of knots and 3-manifolds has been developed since Jones and Witten. We have studied a geometric aspect of the colored Jones polynomial. Some of the colored Jones polynomial was shown to have a nearly-modular property.We have applied a method of the Ramanujan mock theta function to the superconformal algebra. We have studied "moonshine" phenomena which suggests a strange relationship between Fourier coefficients of mock theta function and irreducible representation of finite groups.